Screw-propeller



(No Model.) v G. H. GERE. SCREW PROPELLER.

No. 559,890. Patented May 12, 1896.

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GEORGE H. GERE, OF GRAND RAPIDS, MICHIGAN.

SCREW-PROPELLER.

SPECIFICATION forming part of Letters Patent No. 559,890, dated May 12,1896.

Application filed September 18, 1895. Serial No. 562,834. (No model.)

zen of the United States, residing at Grand Rapids, in the county ofKent and State of Michigan, have invented certain new and usefulImprovements in Screw-Propellers; and 1 do hereby declare the followingto be a full, clear, and exact description of the invent-ion, such aswill enable others skilled in the art to which it appertains to make anduse the same.

My invention relates to improvements in screw-propellers, and moreparticularly to that class of propellers having reversible blades,whereby the action of the same is reversed without reversing the drivingmechanism, and its object is to provide the same with certain new anduseful features hereinafter more fully described, and particularlypointed out in the claims, reference being had to the accompanyingdrawings, in which- Figure 1 is a section on the line 1 1 of Fig. 2 of adevice embodying my invention; Fig. 2, a section of the same on the line2 20f Fig. 1; Fig. 3, a section on the line 3 3 of Fig. 2, and Fig. 4: aside elevation.

Like letters refer to like parts in all of the figures.

A is a drivin -shaft, adapted to be moved longitudinally from inside theboat in any suitable manner and having the reduced portions A A" nearits end, one of said reducti ens, A, having flattened sides A'. Firmlysecured on said reduced portion A, by means of a nut in the end of saidshaft, is the hollow hub B, on which are journaled, in bearings B, theblades 0, which blades are provided with shanks 0, held in said bearings13 by means of nuts and washers. Secured to said shanks by means ofsplines D are sectors D, which sectors engage with racks formed bycutting away portions of the sides of the sleeve F and forming teeth onthe lower edges of the openings thus made through said sleeve. Saidsleeve F engages the reduced portion A of said shaft, which has theflattened sides A and has an inner surface to conform to that of theshaft, thus preventing said sleeve from turning bn said shaft, butallowing a free longitudinal movement of said shaft, said sleeve beingprevented from moving longitudinally by a flange F on its inner end,which engages a casing II, said casing being adapted to receive ascrew-threaded follower G, which is attached, by means of bolts, to theboat, and interposed between said flange and casing and flange andfollower are rings of fiber I to prevent friction and wearing. A sleeveJ on said shaft engages a screw-threaded opening in said follower, and,extending through the boat, has a stuffing-box K on its inner end toprevent the water from entering the boat. The blades 0 are soconstructed that theline of each axis does not pass through the centerofthe blade, but is farthest from the lead side, thus making an unbalancedblade.

To reverse the motion of the boat, the shaft A is moved inward, carryingwith it the hol low hub B and blades O, and as said blades are connectedwith said sleeve by means of the racks and sectors said blades will beretated to the position shown in dotted lines in Figs. 1 and a as saidhub B slides over said sleeve, moving said sectors along said racksuntil the end of said sleeve comes in contact with the end of the cavityin said hub. To again give the boat a forward motion, said shaft ismoved outward until the shoulder formed by the reduction A strikes theinner end of the sleeve F, determining the throw of the blades.

lVhen said propeller is revolved in the direction indicated by thearrows in Fig. 3, with said blades in their maximum positions forforward motion, there being a greater amount of surface to be contactedby the water on the lead side of the axial line of said blades, theforce of said water will tend to throw said blades farther in thatdirection, and thus the same are held in said maximum position, and whensaid blades are reversed and said sides pass said axial lines the actionof the water throws said blades into their maximum positions in theother direction and holds them there the same as before. I thus secure ascrew propeller having reversing blades, which blades are thrown totheir maximum pitch or position by the action of the water after passingthe center of throw, the water then tending to hold the blades when thewheel is rotated at the maximum pitch or position.

It will be observed that by employing a

